Human eye movements as a model of visual prediction

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Eye movements have an important function to stabilize gaze during self-motion, and to shift gaze to locations or objects of interest. Because of their close connection to visual perception, eye movements provide an excellent model system to answer fundamental questions about brain mechanisms underlying vision and movement. Most of our research relies on smooth pursuit eye movementsthe eyes' key response to visual-object motion. In our previous NSERC-funded research, we have characterized and compared the visual signals that drive perception and pursuit, and discovered similarities and striking dissociations between perception and action.Recently, we found that pursuit eye movements provide an important performance advantage during tasks that require prediction. Many real-world movements, such as intercepting prey or hitting a ball, involve prediction of an object's trajectory from a brief glance at its motion. The decision whether, when and where to intercept is based on the integration of current sensory object information, like a baseball's spin or speed, with past sensory experience, like the probability of a curveball. The efficacy and timescale of the mechanisms underlying the integration of current and past sensory signals are poorly understood.We will develop novel experimental paradigms and rely on a combination of technological approaches including human visual psychophysics, eye tracking, hand tracking, and computational modeling to investigate these integration mechanisms. We will manipulate sensory experience at different levels of processingfrom low-level expectations about the occurrence of a particular object motion to high-level rules and heuristics.Establishing the temporal dynamics of integrating and accumulating information during visual prediction will significantly contribute to our understanding of visual and motor control. Moreover, our experimental paradigms have high ecological validity for many natural tasks such as ball sports, and can be translated into portable applications for skill testing and training. The diverse combination of techniques and our multi-disciplinary and collaborative research approach will provide trainees with an ideal research environment.